Apparatus for electrocoating striplike material



Jan. 22, 1952 E. w. RIEGER APPARATUS FOR EILECTROCOATING STRIPLIKE MATERIAL 3 Sheets-Sheet 1 Original Filed Aug. 7, 1944 ger Jan. 22, 1952 E. w. RIEGER 3, 6

APPARATUS FOR ELECTROCOATING STRIPLIKE MATERIAL Original Filed Aug. '7, 1944 v 3 Sheets-Sheet 2 Tlg.

Jan. 22, 1952 E. w. RIEGER 23,456

APPARATUS FOR ELECTROCOATING STRIPLIKE MATERIAL Original Filed Aug. 7, 1944 I5 Sheets-Sheet 5 'eg er PATENT F Re. 23,456 FlCE APPARATUS FOR ELECTROCOATING STRIPLIKE MATERIAL Ernest w. Riege'r, Bloomingdale, Ohio, assignor to National Steel Corporation, a corporation of Delaware Original No. aseasrs, dated October 2, 1951, Se-

rial No. 548,406, August 7, 1944. Application for reissue November 5, 1951, Serial No. 254,820

6 Claims.

Matter enclosed in heavy brackets I: appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

The present invention relates the electrocoating of strip-like material, and more particularly to the coating line where the electro-deposited metal is applied to the base material. My invention is particularly applicable to the manufacture of tinplate by the electrolytic process and a base metal is coated with another metal by an I with it a substantial amount of the electrolyte electro-deposition process.

Several diflerent processes of manufacturin tinplate by the electrolytic method have been employed heretofore. In one process employed com.- mercially the strip is continuously fed through a bath in which bars of tin are suspended, the strip being passed vertically upwardly and then downwardly past the tin bars which form the anodes of the electric circuit. In this process the strip is simultaneously coated 'with' 'tin "on both sides. In another process which has been used heretofore commercially, the strip is passed continuously through one series of tanks or cells con: taining the tin anode bars and the strip coated on one side only. In this process, the strip is then passed through a second series of plating cells in which the other side is similarly coated. My invention is particularly applicable to this latter process, due to the fact that there is an appreciably greater amount of the electrolyte carried from the plating cells by the strip in this process than in the process in which the strip is passed vertically upwardly and downwardly in the bath and simultaneously coated on --both sides. However the principles of my invention 1.. n 2 and from the storage tank back to the cells ls desirable in order to obtain uniformity in the deposition of the tin on the strip. However as will be pointed out hereinafter, excessive circu lation is highly undesirable for variousreasons.

The strip, in normal operations, passes through the plating cells at a relatively high rate of speed. The speeds normally employed are in the neighborhood of 500 to 1000 or more feet per minute. Where such speeds are employed the strip, due to its forward motion, drags or carries and causes it to discharge from each cell at the strip discharge end thereof: The strip discharge end of each cell is normally open from a point below the surface of the electrolyte bath and consequently there is normallysome flow of the elec-' trolyte from the tanlr at this point. However, where speeds such as those'mentioned above are employed, this normal spillage is supplemented by the amount dragged forward by the strip and is are applicable to and'may be employed in either type of process;

In the process in which the. strip is coated-first on one side and then on the other side the strip passes successively through a series of plating tanks or cells. Each plating cell has in it a plurality of tin anode bars which are immersed in the electrolyte. The strip passes through each cell above the anode bars and substantially at but nevertheless slightly below the surface of the electrolyte bath contained in the cell.- The strip forms the cathode of the. electric circuit and passes between a contact roll and a backing roll on the strip entry and of each cell. v v

Due to the fact that the electrolyte must come in contact with the strip as it passes through each cell, there is a constant outflow of the electrolyte from the cell regardless of' the speedfat which the strip passes therethro'ugh." Some circulation of the electrolyte from the cells to a storage tank objectionably large for several reasons. The'discharged electrolyte is deposited in trays positinned-belowthe cells and from each tray it is carried to the storage tank for recirculation through the cells.

. It has been the practice heretofore to allow .the electrolyte to flow over the sides of each plating cell and also over the strip entry end as well-as over the strip discharge end. Due to the substantial nature of this spillage an extremely high pumping rate has been required in order to maintain a proper amount of the electrolyte in each cell. Where a high circulation rate is required as a result of the substantial spillage of'the electrolyte from each cell, objectionable aeration of the electrolyte is encountered. The aeration of the electrolyte results in the conversion of stannous chloride in the electrolyte to the relatively insoluble stannlc chloride. As a consequence,- a sludge is formed inthe plating cells and in the storage tankand recirculating apparatus. Where a high. degreev of aeration is encountered, a high rate of sludge formation is likewise encountered.- Tests have shown that the rate of sludge formation is substantially, directly proportional to the pumping rate required to replenish the electrothe discharged electrolyte strikes the liquid surface in the tray positioned below the cells and' lyte discharged from the cells by spillage.

Aeration of the electrolyte is caused by several diiierent factors. Where the strip pulls the electrolyte from thecells at a relatively high rate,

considerable aeration takes place at this point.

electrolyte enterseach conduit there is a 'substantial amount of turbulence which results in aeration of the liquid. Some of the electrolyte is discharged over the sides of the cells and it this discharge is at a relativel low rate and'the liquid falls into the trays in the form of a film, only a small amount of aeration takes place. However,

frequently the liquid cascades downwardly over the sides of the cells and an appreciable amount of aeration takes place. This is particularly true adjacent the strip discharge end of each cell.

In accordance with the present invention I provide apparatus appreciably reducing the aeration of the electrolyte and the pumping rate required to keep the cells supplied with the electrolyte. In the apparatus which. I provide discharge of the electrolyte over the sides of each cell is eliminated as the sides extend upwardly from the bottom wall to above. the level of the electrolyte .under normal operating conditions. The flow of the electrolyte from. each cell is in a direction opposite to the dlrectionof travel of the strip and v 6 is a partial se tional view taken alon the line VI-VI of Figure 4.

In the aparatus shown in the drawings, the strip 8 passes from the immediately preceding cell or. in the case of the first cell in the line.

- from the pretreating apparatus between a pair is discharged over an end wall or weir at the strip entry end of the cell. Thebody oi the-electrolyte has a quiescent level above the plane of the strip when the strip is stationary during nonoperatingperiods. This quiescent-level is also above the end wall or weir at the entry-end of the cell or tank. The electrolyte is dragged along in the direction 'of travel of the strip by the strip during operating periods andin order to prevent discharge of any substantial amount of the electrolyte from' the strip discharge end .of the tank a dam-is provided. The dam includes an electrical-current strip contact roll andja pressure roll which is utilized to press thestrip into en-, gagement vwith the contact. roll. The roll pass formed by the rolls is in substantially the same horizontal plane-as that in which the strip lies during its passage through the tank. This plane. as is stated above, is below the quiescent level of theelectrolyte. The dam also includes sealing means extending between the walls of the tank or cell at the discharge end and the rolls and in this manner any-substantial discharge of electrolyte at thedischarge end of the cell is eliminated. with this arrangement electrolyte is discharged from each cell only at the strip entry end, except for the small amount of leakage which will normally take place at the strip discharge end. However, the amount discharged at the strip en try end is only a small fraction of that discharged from each cell in the presently known ty es or apparatus and, as a consequence, aeration of the electrolyte is minimized, the pumping rate required to keep the proper amount of-electrolyte in each cell is reduced and the sludge-forming rate is also reduced. Thus substantial savings'in operating costs are effected.

In the accompanying drawings, I have shown, for purposes of illustration only, a preferred em: bodiment of my invention; In. the drawings,

, f-Flgure l is a planview of a portion ofan electro-coatlng line embodying my invention;

Figure 2jis acentral, vertical longitudinal section through the apparatus shown in Figure 1;

Figure 3 is a transverse vertical section taken. along the line III+I1I of Figure 1;

Fi ure 4 is a plan View of a portionof the ap- Perms wn in ure 1 adjacent the stripdischarge end of the cell;

.Figiire is an enlarged sectional view showinsa portronorthe apparatus. adjacent the strip discharge end cithe cell; and w I of rolls comprising a contact roll 2 and a backing roll 3. These rolls are positioned at the strip entry end of. the initial cell in the line and are positioned between each of the cells in the line. The contact roll 2 is provided with necks 4 which cooperatewithelectrical apparatus (not shown) forming a part of the electrical circuit. The roll 31s merely a backing roll and is ordinarily formed of hard rubber.

After the strip passes between the rolls .Zand '3, it passes into the'plating cell which is indicated generally by the reference character 5. The cell 5 contains a plurality of anode bars 6 of tin. One end of each anode bar is. supported on an insulated member I and the other end is supported on a carbon block 8 which forms a part of the electrical circuit; The carbon block, at one side of the cell, isjprovided with bars 9 which are connected to electrical apparatus for supplying cur rent to the system. The cell 5 contains the electrolyte bath, the level of which is normally slightly above the level of the strip. The elec trolyte is fed to the cell either by a conduit opening through the bottom of the cell or by a pipe or hoseillljili'ig. .3 located above the strip level and arranged to discharge the electrolyte onto the surface of the strip. or in both ways. Ihave found that it isdesirable to supply the electrolyte in the latter way because itresults in covering. the topsurface of the strip with the electrolyte. If-thisisinot done, the tinning of the top surface in later operations is not uniform.

the strip passes through the cell, tin is de- I posited from the anode-bars 6 onto the strip. The strip passes from the cell at the end opposite the entry end and passes between the cons tactroll! and the backing roll 3 adjacent the strip entry end of the next preceding cell.

Reference is hereby made to the copending complicationv of Clarence J. Klein, Serial No. 523,681 'nled February 24, 1944, now Patent Number 2.509304, fora more complete description of a tinning line of the general type described above.' 1 As stated above, the strip carries a substantial portion :of the-electrolyte forwardly through the cell, and, in the absence of means for preventingit theielectrolyte flows over the end wall lii'at the discharge end or the cell and is de posited in a tray II which extends beneath the discharge end of one cell and the entry end of'the next-succeeding cell. Also some of the electrolyte is normally" withdrawn from the cell at the discharge end thereof through downcomers l2.:whichdischarge the electrolyte into the tray 1]..

In accordance with my invention, provision is made to'substantially. eliminate the discharge of the'electrolyte over the end wall Ill of the cell and over the side walls '2 I. The end wall H] has a horizontal portion l3 which carries an exten:

" sion member II which partially bridges the area caste will resist the action of the electrolyte and which will withstand the wear or the rotating roll 3. The extension II and the resilient bridging member IE completely bridge the area from the end wall- I to the backing roll 3 so that electrolyte cannot ilow downwardly over the end wall into the collecting tray [l0]11.

In order to prevent the electrolyte from flow ing sidewise adjacent the rolls 2 and 3. side plates or members 2|) are provided. Each side plate constitutes an extension of a side wall 2| oi the cell. Each side plate 20 has anarm 22 which extends generally parallel to the plate 20 and is Joined to the plate to form a section fitting over the end of the adjacent side wall of the cell. The'plate 20, the arm 22 and the side wall 2| are all preferably formed of sheet metal provided with'a heavy layer of rubber. In fact, all of the part of the apparatus coming in contact with the electrolyte, except those parts necessary to the establishment of the electrical circuit, are coated with rubber or some similar material which is resistant to the electrolyte. Each side plate 2| extends forwardly toward the rolls 2 and 3. The

forward end of each plate 20 is cut away "to accommodate the necks of the rolls. The front end of each plate 20 preferably extends to or slightly beyond the axis of the rolls.

Heretoiore in electro-tinning lines of the character illustrated in the drawings, the sides 2| of each cell extended upwardly slightly above the walls at the strip entry and discharge ends. As a consequence, considerable spillage took place over the side walls near the exit end and troughs were provided for collecting this spillage. In accordance with my invention the sides 2| are extended upwardly beyond the end wall 25 at the strip entry end and of course higher than the end wall HI at the strip discharge end of the cell. At the strip entry end, the side walls are sufliciently high to preclude any spillage of the electrolyte thereover; At the other end of the cell these walls must be somewhat higher in view of the fact that the strip pulls the electrolyte through the cell and causes it to pile up to an appreciable extent ahead or the rolls 2 and 3. The side walls 2| need not extend vertically quite as high as the extension side plates 20 in view of the fact that the electrolyte build-up is highest immediately in front of the rolls.

The side walls 2|, the side plates 20, the extension member I4, and the resilient bridging member ID prevent sidewise spillage of the electrolyte and also prevent any substantial amount of the electrolyte from being discharged from the strip discharge end of the cell into tray II. The side plates 20 and members It and l8 c0- operate with rolls 2 and 3 to form in efiect a dam preventing the dragging of electrolyte therebeyond. Of course all leakage at this end of the cell cannot be prevented in view of the fact that leakproof joints cannot be provided between side plates 20 and the necks of the rolls 2 and 3 but this leakage is extremely small and is of no consequence where the apparatus just descr bed is employed.

In view or the tact that spillageover-thelstrip discharge end of the cell is. prevented and in view of the fact that sidewise spillage is prevented, the electrolyte flows rearwardly through the cell and is discharged' over the-end wall 25. The end wall 25 is in the shape of an inverted U, the one leg of the U extending downwardly to a short distance above the bottom of the tray [I0] 11 so that there will be aminimum amount of aeration of the electrolyte at'this point. It the electrolyte were permitted to spill into the tray [I0] 11 from approximately the strip level considerable aeration would take place at this point.

Where the apparatus just described is employed, it is not necessary, and in most cases it is undesirable, to withdraw any portion of the electrolyte from the cell through the downcomers |2. As a consequence these downcomers are normally closed by plug valves '26 innormal operations. However if desired a small amount of the electrolyte may be continuously withdrawn from the cell through these downcomers.

As stated above, where apparatus of the char-.

acter Just described is employed, aerationis reduced to a minimum, the;pumping rate'is reduced to a small traction-oi what would be required without my improvements and sludge formation is reduced appreciably. As a consequence, operating costs are materially reduced and a more efficient, high speed tinning line "is provided.

While I have shown and described a preferred embodiment 01' my invention, it will be understood that my invention is not limited thereto but may be otherwise embodied within the scope of the appended claims.

I claim:

1. In apparatus for progressively electroplating strip, the combination comprising, a tank tion to the tank, an electroplating anode disposed in said tank below the path of the strip, said tank having a bottom wall, side walls extending upwardly from' the bottom wall above the path of the strip across the tank for preventing spillage oi' electroplating solution across the side walls, an entry-Lend wall extending upwardly from the bottom wall toward the path of the strip and terminating below the path of the strip and below the sidewalls, said-tank bein free of means preventing the spillage of solution across the top'oi the entry end wall and said entry end wall forming a di'schargeweir for the solution at the entrance end of the tank, and an exit end wall at the exit end of-the tank extending upwardly from the bottom wall toward the path of the strip, said strip moving means comprising a pair 01' strip engaging rolls including an upper roll and a lower roll adjacent the discharge end of and-positioned outside of the tank, one of said rolls being a contact roll for making electrical contact with the strip, means for connecting the contact roll and the anode to a source of electric current, sealing means extending between each of the side walls of the tank and the rolls and sealing means extending between at least one of the rolls and the exit end wallot the tank, the sealing means with the rolls preventing the spillage of electroplating solution from the exit end of the tank so that substan ial y all or e P l fe ep- 2. In apparatus for progressively electroplating; strip, the combination comprising; a tank for: holding a bath of electroplating solution, means for moving; the strip along a horizontal path across; the tank from; the entry end to the exit" end whereby the moving strip drags electroplating solution in the direction of" strip travel; for electroplating solu-.. tion to the. air electroplating anode disin said tonic below the path of the strip,

havinga wall; sidewalls extending upwardlyfrom the bottom wall abovethe path ofthe' strip? across the tank for ma venting spillageof electroplating solution across the side walls, a'n wall extending upwardly from the bottom wall toward the path of the stripand" tenninating below thepath; of: the

strip and the -side walls, said tank being:

free: ofi means preventing. the spillage'of-z solution the topoh the entryend: wall and said: will forming a discharge weirfor' the solution at: the entranceendof the tank,

and anexit.- endiwalliatatme exit end of the tank extending from the bottom wall; toward the-v m strip, said stripmoving:

i a; pain on strip engaging 'roils including an uppon and: a-- lowerroll. adja centthe discharge end ori anda positioned outside of the tank, one of said rolls being a contact roll" to: contact with the strip and j each, of? having: at eachend a rol'atinelyrsmalim romneek, means for; connect; 1 3- h w t chmll the anode to. a, source of electric current; a, side wall. extension for each side wall having demountablev sealing; con nection therewith. and extending forwardly to the lower and. cut: away at, the forword end" to; engage. the; periphery of the correspondingroli: mole of the lower roll, and sealh1g1 means; extendimn from the. said exit endwal'llof thetanktmsaidflower-roliiwhieh togetherwith said-side wall ionsrorm a container forholding the solution and, for: restraining the spillage. of? electroplating solution from the exitv end so that .substantiallyall or the spillage of. elsctroplatins: solution. from tankis end wall :infiflfiflfi coat: .7

across, mutant; means; [extends his beneathll mm and of th tan v forcollecting the solution spilling over theentry be the, tanln.

3. In apparatus for progressively electroplating strip, the combination comprising, a tank for holding; a bath oi? electroplating solution. means for moving strip along a-:-,-hOr.izontal,- path across the from the entry: end to the exit end whereby the moving strip drags e1ectro-. plating solution in the direction of strip travel, means for supplying electroplatingsolution to the tank; an electroplating anode disposed in said tankbelow the path of the strip, said tank having a bottom wall, side walls extending upwardly' from the bottom wall abovethe'path of the strip the for preventing spillage of electroplahng solution across the side walls, an entry end ellltei'idlnk upwardly from the bottom wait the path or the strip and in the dire tion, f trip 5 8 patlroi the strip and below the side walls, saidta'nk free of means preventing the spillage of solution across the top of" the rntmwemiv wall and; said entry end wall forming a discharge weirfor the solution at the entrance end of the tank, and an exit end wall at the exit endofthetankextending upwardly from the bottom-wall toward'the path of the strip, said strip=moving means comprising a pair of strip engaging rolls including an upper roll and a lower roll adjacentthe discharge end of and positioned outside of thetank, one of said rolls being a contact roll=v for making electrical contact withthe strip and each of said rolls having at each end arelatively smaller roll neck, means for connecting the contactroll and theanode to a source of electric-current,- a side wall extension foreach side wall and having demountable sealing connection therewith and extending" forwardly intoengagement with the ends: of the rolls and being -cut' away at the forward ndtoengage the: periphery of the corresponding roll necks with-a portion at the forward endextending betweenthe roll necks, and a sealing means extending from the-isaide xit end wall or the tank tosaid'lower roll: which together with said side: wall extensions formv a container for holding the. plating solution and for restraining the spillageofelectroplating solution from the exitend of the-tank sothat-lsubsta-ntially all of the spillage of' electroplating solution from the tank-is across theentr'y end: wall in a direction countercurrenta to direction of:- strip move. ment' across the tank, and? meansv [extending beneathlat theientry end ofrtheltank for 001- lecting the electroplating solution spilling overthe entry end; wall: of the tank.

4. Inapparatus for progressively, electroplating strip, the combination: comprising, a tank for holding arbath of: eieotrpplating solution, means for moving; the strip along a horizontal pathacrossthentanlsfrom, the entry; end to the exit end whereby the moving; strip qrags electroplating: solution, the direction of I strip travel, means fo sup lying lectr p ati so ut to the tank elecho a ns; no disposed, said'i ank; belowthepa-thmf the strip, said tank having a bottom wallside walls; extending up-. wardlysfromihebottom wall above thepath of the-strip-across the; tank for preventing spillage of, electroplating; solution across the side walls, an: entry! end. wall extending upwardly from the bottom, wall towfl id the p a'th; of the strip and terminating belpw the pathofthe strip and below t e side; wal s aid, ank beingv r f means p ev ntinszthasp llasaqi lu ion a ross h op ot: h entry and. wall -ad said. entr d Wall,

forming a,discharge weir for thesplution at the entrancfl. Ghdnf. the, tank and an exit end wall at, the. exihendof the tank extending upwardly from he bottom all ow d. he t of the ting. said-strinmoving means comprising a pair f. str p, en aging; mils n ludin an p er l and; a owe roll ad acent th d s ha g end 0t nd posi ioned, outside, o h ank. o of i rolls being a. contact rollgfor making electrical, contact with the strip, means for connecting the contact roll and the anode to a source of electric current, a side wall extension for each side wall, each side wall extension including a member extendingfrom the side; wall forwardly to the lower roll and" a parallel arm spaced from and Jo d. at n to h m m c h me r and arm fittingover-the end of thecorresponding side wall and forming-a demountable connection; therewith, and a sealing means extending from the exit end wall to said lower roll which together with said side wall extensions of the tank form a'container for holding the plating solution and for restraining the spillage of electroplating solution from the exit end of the tank so that substantially all of the spillage of electroplating solution from the tank is across the entry end wall in a direction countercurrent to the direction of strip movement across the tank, and means [extending beneath] at the entry end of the tank for collecting the electroplating solution spilling over the entry end wall of the tank.

5. In apparatus for progressively electroplating strip, the combination comprising, a tank for holding a bath of electroplating solution, means for moving the strip along a horizontal path across the tank from the entry end to the exit end whereby the moving strip drags electroplating solution in the direction of strip travel, means for supplying electroplating solution to the tank, an electroplating anode disposed in said tank below the path of the strip, said tank having a bottom wall, side walls extending upwardly from the bottom wall above the path of the strip across the tank for preventing spillage of electroplating solution across the side walls, an entry end wall extending upwardly from the bottom wall toward the path of the strip and terminating below the path of the strip and below the side walls, said tank being free of means preventing the spillage of solution across the to 01' the entry end wall and said entry end wall forming a discharge weir for the solution at the entrance end of the tank, and an axit end wall at the exit end of the tank extending upwardly from the bottom wall toward the path of the strip, said strip moving means comprising a pair of strip engaging rolls including an upper roll and a lower roll adjacent the discharge end of and positioned outside of the tank, one of said rolls being a contact roll for making electrical contact with the strip, means for connecting the contact roll and the anode to a source of electric current, a side wall extension for each side wall, each side wall extension including a member extending from the side wall forwardly to and into engagement with the rolls and a parallel arm spaced from and joined at one end to the member, the member and arm fitting over the end of the corresponding side wall and forming a demountable connection therewith, and a sealing means extending from the exit end wall to said lower roll which together with said side wall extensions of the tank form a container for holding the plating solution and for restraining the spillage of electroplating solution from the exit end of the tank so that substantially all of the spillage of electroplating solution from the tank is across the entry end wall in a direction countercurrent to the direction of strip movement across the tank, and means [extending beneath] at the entry end of the tank for collecting the electroplating solution spilling over the entry end wall of the tank. 6. In apparatus for progressively electroplat ing strip, the combination comprising, a tank for holding a bath of electroplating solution, means for moving the strip along a horizontal path across the tank from the entry end to the exit end whereby the moving strip drags electroplating solution in the direction of strip travel, means for supplying electroplating solution to the tank, an electroplating anode disposed in said tank below the path of the strip, said tank having a bottom wall, side walls extending upwardly 10 from the bottom wall above the path of the strip across the tank for preventing spillage of electroplating solution across the side walls, an entry end wall extending upwardly from the bottom wall toward the path of the strip and terminating below the path of the strip and below the side walls, said tank being free of means preventing the spillage of solution across the top of the entry end wall and said entry end wall forming a discharge weir for the solution at the entrance end of the tank, and an exit end wall at the exit end of the tank extending upwardly from the bottom wall toward the path of the strip, said strip moving means comprosin-g a pair of strip engaging rolls including an upper roll and a lower roll adjacent the discharge end of and positioned outside of the tank, one of said rolls being a contact roll for making electrical contact with the strip and each of said rolls having at each end a relatively smaller roll neck, means for connecting the contact roll and the anode to a source of electric current, a side wall extension for each side wall, each side wall extension including a member extending from the side wall forwardly to and into engagement with the ends of the rolls and being cut away at the forward end to engage the periphery of the corresponding roll necks with a portion at the forward end extending between the roll necks, and a parallel arm spaced from and joined at one end to the member, the member and arm fitting over the end of the corresponding side wall and forming a demountable connection therewith, and a sealing means extending from the exit end wall to said lower roll which together with said side wall extensions of the tank form a container for holding plating solution and for restraining the spillage of electroplating solution from the exit end of the tank so that substantially all of the spillage of electroplating solution from the tank is across the entry end wall in a direction countercurrent to the direction of strip movement across the tank, and means [extending beneath] at the entry end of the tank for collecting the electroplating solution spilling over the entry end wall of the tank.

ERNEST W. RIEGER.

REFERENCES CITED The following references are of record in the file of this patent or the original patent:

UNITED STATES PATENTS Number Name Date 1,191,386 Battle July 18, 1916 1,242,695 Hood Oct. 9, 1917 1,484,653 Kirschner Feb. 26, 1924 2,024,248 Rafton Dec. 17, 1935 2,093,238 Domm Sept. 14, 1937 2,271,736 Hall Feb. 3, 1942 2,307,923 Hogaboom Jan. 12, 1943 2,324,652 Stoker July 20, 1943 2,344,548 Goetz Mar. 21, 1944 2,377,550 Hall June 5, 1945 2,384,660 Ward Sept. 11, 1945 2,490,055 Hoff Dec. 6, 1949 FOREIGN PATENTS Number Country Date 467,019 Great Britain June 9, 1937 OTHER REFERENCES Weirton Steel. 

